Small scientific knowledge around younger students discover a lot!

1. Why do stars twinkle? We see twinkling stars not because of change in luminosity of stars themselves, but because of occlusion of atmosphere. There is an atmosphere between us and stars. As starlight passes through atmosphere, it is affected by density and thickness of atmosphere. The atmosphere is not absolutely transparent, its transparency depends on density. Therefore, when we look through it at earth at stars, we see that stars seem to twinkle.

2. Why do people yawn? When we feel tired, body produces a lot of carbon dioxide. When there is too much carbon dioxide, oxygen must be added to balance body's needs. Since this residual carbon dioxide will affect functional activities of our body, at this time body sends a defensive reaction, so we yawn. Yawning is a deep breathing action that will allow us to take in more oxygen and expel carbon dioxide than usual, as well as eliminate fatigue.

3. Why can snakes walk without legs? Snakes have a lot of scales, which is outer layer of armor on their bodies. The scales are used not only to protect body, but also their "legs". When snake crawls forward, its body will take shape of an S. Each scale outside of S-shape will be raised to help snake grab onto uneven road as it moves forward. These scales interact with snake's muscles and can push body forward to crawl, so the snake can walk without legs!

4. Why do sunflowers always bloom towards sun?The stem under a sunflower disc contains a substance called "plant auxin". This substance has function of accelerating reproduction, but it has an anti-rotation property: every time it encounters light, it goes to side that is not lit.